Friction shock absorber for trucks of railway cars



Oct. 21, 1952 w. E. wlTHALL FRICTION SHOCK ABSORBER FOR TRUCKS OF RAILWAY CARS Filed July 16, 1949 InVen/[o:

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Patented Oct. 21, 1952 FRICTION `SHOCK ABSORBER FR TRUCKS OF RAILWAY' CARS' William El `Withall, Hinsdale, Ill., assigner .to W. H. Miner, jInc.,Chicago, Ill., acorporati'on of Delaware .Appli-mation `July is, 1949seria1no. 105,157

(c1. soif-9) 52 Claims. 1 This invention `relates to improvements `in friction shock'` absorbers especially adapted for dampening or snubbing the action of railway car truck springs.

One object of the invention is to provide a friction shock absorbing mechanism, comprising a friction casing, friction shoes slidingly telescoped within the casing, a rubber element yieldingly opposing movement of the shoes inwardly of the casing, a pressure transmitting member, and a rubber cushioning means compressible between `said pressure transmitting member and shoes,

adapted to be expanded in transverse direction when compressed to force saidshoes against the friction surfaces of the casing.

A more specific object of the invention is to provide a mechanismas set forth in the preceding paragraph, wherein the rubber cushioning means, whichis compressble between the pressure transmitting member and shoes, comprises a plurality of rubber discs alternated with metal spacing plates.

Other objects of the invention will more clearly appear from the description and claims herein* after following. I

In the accompanying drawing forming a part of this specification, Figure l is a vertical sectional view of my improved shock absorben corresponding `substantially to the line I-I `ofligure 2. Figure 2 is a top plan view of Figure l. Figure 3 is a view, similar to Figure l, showing the mechanism fully compressed. Figure fl is a broken, vertical sectional view, corresponding substantially to the line fl--Jl of Figure 2.

As illustrated in the drawing, my improved shock absorber comprises broadly a friction casing A, three friction shoes B-B-B, a pressure transmitting plunger C, a rubber element D yieldingly opposing inward movement of the shoes, and a cushioning unit comprising a pair of radially expandible rubber pads E-E and spacing plates F-F-F, between the shoes and compressible by the plunger C to force the shoes radially apart against the friction surfaces of the casing.

The casing A is in the form of a tubular mem-- ber of substantially hexagonal, transverse cross section. The casing A is open at its upper end and has a transverse bottom wall Ill at its lower end. At the upper end of the casing, the walls thereof are providedwith interior, inwardly converging friction surfaces I I-I I-I I of V-shaped, transverse cross section. The open upper end of the casing is further provided with three interior stop lugs I2--I2-I2, which are alternated with the three friction surfaces. The bottom wall. Il() of the casing is` provided with a central opening I3 therethrough, `aclapi-,ed'to .accommodate the usual spring centering projections of the bottom spring plate of the `cluster of truck springs of a railwaycar. l

The three friction shoesB-.B-B are of similar design, each shoe comprising an upstanding platelike section I-ll of vi-shaped, `horizontalcross section, having an inwardly projecting, horizontal flange I5 at its lower end. The flange I5 .is of substantially triangular outiineas shown most clearly in Figure 2. On its outer side, eachfshoe also presents a lengthwise extending frict-ionsurface H5 of V-shaped, transverse section, engaged with one lof the V-shaped yfriction surfaces i i of the casingA. I I

The rubber element D is disposed within the casing A, below the shoes B--B-B.` The element .D is in the form of anelongated, solid, cylindrical block, slightly tapered toward its `top and fbottom ends, as shown in Figure l. The block-like rubber element D is supported on adisc or plate I-'I, which, .in turn, is supporteolon the wall |10 of the casing and closes the opening I 3 of said wall. The upper end of the element i3 bears on the underneath sidesV of the `flanges I.5,-.I5-I'5 of the shoes B-B-B. l The pressure transmitting plungerC isin'the form of a hollow, cylindrical block having a laterally projecting, peripheral ange I8 at its upper end, overhanging the open upper end of the casing A. The plunger C projects downwardly toward the casing A and between the shoes B-B-B. The hollow plunger C presents a central opening I9 at its upper end of smaller diam- I eter than the interior of the plunger, the opening I9 being adapted to receive the usual spring centering projection of the top spring follower plate of the spring cluster of a railway car truck. At

the inner or bottom end, the plunger C has three laterally outwardly projecting, radial lugs 20 lill-2li, formed on depending fingers 2I-2I2I on said plunger. The lugs 20-20-20 are alternated with the shoes B--B-B, and each lug extends between two adjacent shoes to engage in back of the corresponding lug I2 of the casing and restrict outward movement of the plunger C. The lower end face of the plunger C, which end face is indicated by 22, is engaged lwith the cushioning unit, which is composed of the pads E and E and the plateslL-lL-lil` The plates F are in the form of circular metal discs, alternated with the rubber pads E-E, the bottoni plate F being supported and bearing on the flanges |5--I5--l5 of the three shoes B-B--B, the top plate F bearing on the fiat bottom face 22 of the plunger C, and the third or intermediate plate F being interposed between the two rubber pads E-E.

The rubber pads E--E are of similar design, each pad being in the form of a circular disc or washer. As shown in Figure 1, the upper pad bears directly on the underneath side ofthe top plate F and the lower pad E bears directly on the bottom plate F. Each pad E is of greater diameter than the plates F and projects outwardly beyond the same in bearing contact with the inner sides of the shoes B-B-B- My improved shock absorber preferably replaces onev or more of the spring units of a truck spring cluster, being interposed between the top and bottom spring plates of said cluster.

The operation of my improved shock absorber is as follows: Upon the spring cluster of the truck of a railway car -being compressed between the spring follower plates of the cluster, the plunger C is forced downwardly toward the casing A, compressing the rubber pads E-E between the plates F-FL-F and forcing the shoes B-B-B inwardly of the casing against the resistance of the rubber element D. Compression of the pads E--E spreads the latter radially, forcing the shoes apart into tight frictional contact with the friction surfaces of the casing as they are carried inwardly along said friction surfaces, thus providing progressively increasing shock absorbing capacity. Compression of the shock absorber is finally limited, as illustrated in Figure 3, by engagement of the flange I3 of the plunger C with the upper end of the casing A, thus protecting the rubber pads E-E and the rubber element D against over-compression.

Upon reduction of the actuating pressure on the plunger C, as thetruck springs recoil, the pressure upon the rubber. pads E-E is reduced, permitting the same to contractradially, thereby reducing the radial pressure on the shoes and thus facilitating release of the mechanism, the shoes being returned to the normal full release position shown in Figure 1, by the lengthwise expansion of the rubber element D.

I claim:

1. In a friction shock absorber, the combination with a friction casing having interior friction surfaces at one end thereof; of friction shoes in sliding engagement with said friction surfaces; a rubber element within the casing yieldingly opposing inward movement of the shoes; inturned, horizontal flanges at the inner ends of said shoes; a spacing plate bearing on said flanges; a rubber pad bearing on said spacing plate; a second spacing plate bearing on said pad; a second rubber pad bearing on said second plate; a third spacing plate bearing on said second named pad; and a pressure transmitting plunger movable toward and away from said casing, the inner end of said plunger bearing on said third named spacing plate.

2. In a friction shock absorber, the combination with a friction casing having interior friction surfaces; of friction shoes slidable lengthwise on said friction surfaces, each shoe having an inwardly disposed flange; yielding means within the casing bearing on the flanges of said shoes and reacting between said casing and the flanges of said shoes for opposing inward movement of said shoes; rubber means between said shoes and supported by said flanges, said rubber means comprising rubber pads alternated with metal spacing plates, with one of said plates bearing on the iianges of said shoes; and pressure transmitting means engageable with said rubber means for compressing the same lengthwise against the flanges of said shoes.

WILLIAM E. WITHALL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,933,034 Sproul Oct. 31, 1933 2,010,623 Bugatti Aug. 6, 1935 2,055,242 Smith Sept. 22, 1936 2,205,098 Lamont June 18, 1940 2,402,146 Cardwell June 18, 1946 FOREGN PATENTS Number Country Date 329,870 Great Britain May 29, 1030 620,246 France Jan. l5, 1927 

